Driehuys Bastiaan, Hedlund Laurence W
Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710, USA.
Toxicol Pathol. 2007 Jan;35(1):49-58. doi: 10.1080/01926230601132048.
In vivo magnetic resonance microscopy (MRM) of the small animal lung has become a valuable research tool, especially for preclinical studies. MRM offers a noninvasive and nondestructive tool for imaging small animals longitudinally and at high spatial resolution. We summarize some of the technical and biologic problems and solutions associated with imaging the small animal lung and describe several important pulmonary disease applications. A major advantage of MR is direct imaging of the gas spaces of the lung using breathable gases such as helium and xenon. When polarized, these gases become rich MR signal sources. In animals breathing hyperpolarized helium, the dynamics of gas distribution can be followed and airway constrictions and obstructions can be detected. Diffusion coefficients of helium can be calculated from diffusion-sensitive images, which can reveal micro-structural changes in the lungs associated with pathologies such as emphysema and fibrosis. Unlike helium, xenon in the lung is absorbed by blood and exhibits different frequencies in gas, tissue, or erythrocytes. Thus, with MR imaging, the movement of xenon gas can be tracked through pulmonary compartments to detect defects of gas transfer. MRM has become a valuable tool for studying morphologic and functional changes in small animal models of lung diseases.
小动物肺部的体内磁共振显微镜检查（MRM）已成为一种有价值的研究工具，尤其适用于临床前研究。MRM为纵向和高空间分辨率成像小动物提供了一种非侵入性且无损的工具。我们总结了一些与小动物肺部成像相关的技术和生物学问题及解决方案，并描述了几种重要的肺部疾病应用。磁共振成像的一个主要优势是使用诸如氦气和氙气等可呼吸气体对肺部的气体空间进行直接成像。当被极化时，这些气体成为丰富的磁共振信号源。在呼吸超极化氦气的动物中，可以追踪气体分布的动态情况，并检测气道狭窄和阻塞。氦气的扩散系数可以从扩散敏感图像中计算得出，这可以揭示与诸如肺气肿和纤维化等病理相关的肺部微观结构变化。与氦气不同，肺部的氙气会被血液吸收，并且在气体、组织或红细胞中表现出不同的频率。因此，通过磁共振成像，可以追踪氙气在肺部各腔室中的移动，以检测气体交换缺陷。MRM已成为研究肺部疾病小动物模型形态学和功能变化的有价值工具。
